Unit comes with two 0.5Ω coils. These will work with any 20W+ battery and perform best at 20-35W but can be used at up to 60W. The 2.0Ω coils (purchased separately) will work with any Ego style battery (e.g. Royale) or mod with settable wattage (e.g. eVic VTC Mini, iStick) and perform best at 12-14W but can be used from 10-16W.